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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <h2>异步前戏</h2>
</body>
<script>
    console.log(111)
    setTimeout(()=>{
        console.log(222)
    },0)

    new Promise((reslove,reject)=>{
        console.log(333)
        reslove()
    }).then(()=>{
        console.log(5555)
    })
    console.log(4444)

    //1,3,4,5,2  先同步后异步，异步中，先微后宏
    
</script>
</html>